Ember: how to set classNameBindings on parent element of view - ember.js

Question

See http://jsfiddle.net/4ZyBM/6/
I want to use Bootstrap for my UI elements and I am now trying to convert certain elements to Ember views. I have the following problem:
I embed an input element in a DIV with a given class (control-group). If a validation error occurs on the field, then I want to add an extra class "error" to the DIV.
I can create a view based on the Ember.TextField and specify that if the error occurs the ClassNameBinding should be "error", but the problem is that class is the set to the input element and not to the DIV.
You can test this by entering a non alpha numeric character in the field. I would like to see the DIV border in red and not the input field border.
HTML:
<script type="text/x-handlebars">
<div class="control-group">
{{view App.AlphaNumField valueBinding="value" type="text" classNames="inputField"}}
</div>
</script>
JS:
App.AlphaNumField = Ember.TextField.extend({
isValid: function () {
return /^[a-z0-9]+$/i.test(this.get('value'));
}.property('value'),
classNameBindings: 'isValid::error'
})
Can I set the classNameBindings on the parent element or the element closest to the input ? In jQUery I would use:
$(element).closest('.control-group').addClass('error');

Answer 1

The thing here is that without using jQuery you cannot access easily the wrapping div around you Ember.TextField's. Also worth mentioning is that there might be also a hundred ways of doing this, but the simplest solution I can think of would be to create a simple Ember.View as a wrapper and check the underlying child views for validity.
Template
{{#view App.ControlGroupView}}
{{view App.AlphaNumField
valueBinding="value"
type="text"
classNames="inputField"
placeholder="Alpha num value"}}
{{/view}}
Javascript
App.ControlGroupView = Ember.View.extend({
classNameBindings: 'isValid:control-group:control-group-error',
isValid: function () {
var validFields = this.get('childViews').filterProperty('isValid', true);
var valid = validFields.get('length');
var total = this.get('childViews').get('length')
return (valid === total);
}.property('childViews.#each.isValid')
});
App.AlphaNumField = Ember.TextField.extend({
isValid: function () {
return /^[a-z0-9]+$/i.test(this.get('value'));
}.property('value')
});
CSS
.control-group-error {
border:1px solid red;
padding:5px;
}
.control-group {
border:1px solid green;
padding:5px;
}
Working demo.
Regarding bootstrap-ember integration and for the sake of DRY your could also checkout this ember-addon: https://github.com/emberjs-addons/ember-bootstrap
Hope it helps.

Answer 2

I think that this is the more flexible way to do this:
Javascript
Boostrap = Ember.Namespace.create();
To simplify the things each FormControl have the properties: label, message and an intern control. So you can extend it and specify what control you want. Like combobox, radio button etc.
Boostrap.FormControl = Ember.View.extend({
classNames: ['form-group'],
classNameBindings: ['hasError'],
template: Ember.Handlebars.compile('\
<label class="col-lg-2 control-label">{{view.label}}</label>\
<div class="col-lg-10">\
{{view view.control}}\
<span class="help-block">{{view.message}}</span>\
</div>'),
control: Ember.required()
});
The Boostrap.TextField is one of the implementations, and your component is a Ember.TextField. Because that Boostrap.TextField is an instance of Ember.View and not an Ember.TextField directly. We delegate the value using Ember.computed.alias, so you can use valueBinding in the templates.
Boostrap.TextField = Boostrap.FormControl.extend({
control: Ember.TextField.extend({
classNames: ['form-control'],
value: Ember.computed.alias('parentView.value')
})
});
Nothing special here, just create the defaults values tagName=form and classNames=form-horizontal, for not remember every time.
Boostrap.Form = Ember.View.extend({
tagName: 'form',
classNames: ['form-horizontal']
});
Create a subclass of Boostrap.Form and delegate the validation to controller, since it have to be the knowledge about validation.
App.LoginFormView = Boostrap.Form.extend({
submit: function() {
debugger;
if (this.get('controller').validate()) {
alert('ok');
}
return false;
}
});
Here is where the validation logic and handling is performed. All using bindings without the need of touch the dom.
App.IndexController = Ember.ObjectController.extend({
value: null,
message: null,
hasError: Ember.computed.bool('message'),
validate: function() {
this.set('message', '');
var valid = true;
if (!/^[a-z0-9]+$/i.test(this.get('value'))) {
this.set('message', 'Just numbers or alphabetic letters are allowed');
valid = false;
}
return valid;
}
});
Templates
<script type="text/x-handlebars" data-template-name="index">
{{#view App.LoginFormView}}
{{view Boostrap.TextField valueBinding="value"
label="Alpha numeric"
messageBinding="message"
hasErrorBinding="hasError"}}
<button type="submit" class="btn btn-default">Submit</button>
{{/view}}
</script>
Here a live demo
Update
Like #intuitivepixel have said, ember-boostrap have this implemented. So consider my sample if you don't want to have a dependency in ember-boostrap.